Question

Why is Hess's Law accurate?

Answer 1

Hess' law:

1. According to Hess' law, the path between the beginning and final states has no effect on the change in enthalpy in a chemical reaction (i.e., the heat of reaction under constant pressure).
2. It helps us in the calculation of the enthalpy change($∆\mathrm{H}$) for a reaction even when it cannot be measured directly.
3. According to this, when a reaction is carried out in a series of steps, the total enthalpy change is equal to the sum of the individual step enthalpy changes according to the principle of energy conservation.
4. Since enthalpy is a part of the state, the Hess law is correct.